Vibronic Spectra of Diatomic Molecules and the Birge-Sponer Extrapolation©
Theresa Julia Zielinski
Department of Chemistry, Medical Technology, and Physics
Monmouth University
West Long Branch, NJ 07764-1898
United States
mail to: tzielins@monmouth.edu

George M. Shalhoub
Department of Chemistry
La Salle University
Philadelphia, PA 19141-1199
United States
mail to: shalhoub@lasalle.edu

The goal of this document is to examine the potential energy curve for both the ground and excited state of an electronic transition in order to set the stage for a Birge-Sponer determination of the D0 and De dissociation energies of the excited state of a diatomic molecule from experimental UV-vis spectral data. This document takes advantage of the live symbolics and optimize features of Mathcad 6.0+ to present a derivation of the Birge-Sponer equations. The document contains ample student exercises to foster reflection and learning of the spectroscopic concepts. After using this document students will be able to: explain the relationship between the potential energy curves for excited and ground states in a molecule; explain the significance of each parameter in a Morse potential energy function; and use a Birge-Sponer plot to determine dissociation energy of an electronic excited state of a diatomic molecule. This document will prepare students for analysis of the vibronic spectrum of iodine or some other diatomic molecule. The Iodine Spectrum document, IodineSpectrum.mcd, is the companion template for the analysis of the UV-vis spectrum of a diatomic molecule.

This document is one of a suite of documents treating the vibronic spectra of molecules. The other documents in the set are: MorsePotential, Introduction to Franck-Condon Factors, and the Iodine Spectrum. When used together these documents form a powerful integrated collection of concept builders for students studying spectroscopy in a Junior or Senior college level quantum chemistry course.
Editor's Commentary
Audiences: Upper-Division Undergraduate
Pedagogies: Computer-Based Learning
Domains: Laboratory Instruction, Physical Chemistry
Topics: Mathematics / Symbolic Mathematics, Quantum Chemistry, UV-Vis Spectroscopy
File NameDescriptionSoftware TypeSoftware Version
BirgeSponer.mcd JCE Mathcad Computational Document Mathcad
BirgeSponer.pdf Read-Only Document
BirgeSponerB.pdf Read-Only Document
BirgeSponerB.mw JCE Maple V Computational Document Maple V
BirgeSponerAV.pdf Read-Only Document
BirgeSponerA.mw JCE Maple V Computational Document Maple V
JCE JCE Subscribers only: name and password or institutional IP number access required.
Shalhoub, G. M.; Zielinski, T. J. J. Chem. Educ. 1998 75 1192.
Comments to: Theresa Julia Zielinski at tzielins@monmouth.edu and George M. Shalhoub at shalhoub@lasalle.edu
©Copyright 1998 Journal of Chemical Education